Spying on Americans: Project Shamrock Begins

Government spying on American citizens began during World War I and continued intermittently during the 1920s and early 1930s. It then resumed in earnest in the late 1930s as international tensions and fear of Communist subversion increased (see August 24, 1936). It then intensified during the post-World War II Cold War. One major effort was Project Shamrock, begun on this day, even before the creation of either the CIA or the NSA. Project Shamrock involved monitoring telegraphic messages entering and leaving the U.S. At its height, the program was monitoring 150,000 messages a month. Shamrock was exposed in 1975, and terminated by NSA director Lew Allen that year.

For major exposés of spying on Americans by U.S. intelligence agencies, see TheNew York Times coverageof CIA spying on Americans on December 22, 1974; the Times exposé of NSA spying under President George W. Bush, on December 16, 2005; and the first in a long series of exposes of NSA spying under President Barack Obama on June 5, 2013.